Regarding seamless capsules which have hitherto been used for various applications, substances which can be encapsulated are specifically limited to lipophilic substances such as liquid oil, powder-suspended oil and the like.
Hydrophilic substances are not actually encapsulated in a stable state, because hydrophilic substances generally employ water as a solvent which makes the capsules soften on and after encapsulation.
In Japanese Patent Kokai No. 03-52639, there is disclosed a method for encapsulating a hydrophilic substance wherein a lower fatty acid ester of sucrose is provided between the hydrophilic substance and a film. Although the method actually produces a seamless capsule containing a hydrophilic substance, there is a problem in that the water content of the hydrophilic substance increasingly transfers to the film in the form of water vapor to soften the capsule or adhere to it, particularly at high temperatures (not less than 30.degree. C.). Further, propagation of mold or bacterium is liable to arise with time due to the water content transferred to the film. There is also a quality problem in design.